Can an outdated iPad be updated?

Hello, I'm curious about the potential for updating an outdated iPad. Is it possible to upgrade the software or hardware of an iPad that's a few generations old? How far back can you typically go in terms of compatibility with the latest updates? Additionally, are there any known limitations or drawbacks to updating an older iPad? I'm trying to decide if it's worth investing in updating my current device or if it's time for an upgrade. Thanks in advance for your insights.